Why do I get AttributeError: 'NoneType' object has no attribute 'something'?


I am getting an error message that says

AttributeError: 'NoneType' object has no attribute 'something'

How can I understand this message?

What general scenarios might cause such an AttributeError, and how can I identify the problem?

This is a special case of AttributeErrors. It merits separate treatment because there are a lot of ways to get an unexpected None value from the code, so it’s typically a different problem; for other AttributeErrors, the problem might just as easily be the attribute name.

See also What is a None value? and What is a 'NoneType' object? for an understanding of None and its type, NoneType.

Asked By: Jacob Griffin



NoneType means that instead of an instance of whatever Class or Object you think you’re working with, you’ve actually got None. That usually means that an assignment or function call up above failed or returned an unexpected result.

Answered By: g.d.d.c

You have a variable that is equal to None and you’re attempting to access an attribute of it called ‘something’.

foo = None
foo.something = 1


foo = None

Both will yield an AttributeError: 'NoneType'

Answered By: koblas

The NoneType is the type of the value None. In this case, the variable lifetime has a value of None.

A common way to have this happen is to call a function missing a return.

There are an infinite number of other ways to set a variable to None, however.

Answered By: S.Lott

Trying to use an in-place operation on a mutable object and assign the result back is another common reason for an unexpected None result. For example:

mylist = mylist.sort()

The sort() method of a list sorts the list in-place; that is, mylist is modified, but the actual return value of the method is Nonenot the sorted list.

Thus, the above code causes mylist to become None. Subsequently trying to call e.g. mylist.append(1) will therefore cause an AttributeError.

Answered By: kindall

Consider the code below.

def return_something(someint):
 if  someint > 5:
    return someint

y = return_something(2)

This is going to give you the error

AttributeError: ‘NoneType’ object has no attribute ‘real’

So points are as below.

  1. In the code, a function or class method is not returning anything or returning the None
  2. Then you try to access an attribute of that returned object(which is None), causing the error message.

g.d.d.c. is right, but adding a very frequent example:

You might call this function in a recursive form. In that case, you might end up at null pointer or NoneType. In that case, you can get this error. So before accessing an attribute of that parameter check if it’s not NoneType.

Answered By: barribow

It means the object you are trying to access None. None is a Null variable in python.
This type of error is occure de to your code is something like this.

x1 = None


x1 = None
x1.someother = "Hellow world"

x1 = None

# you can avoid some of these error by adding this kind of check
if(x1 is not None):
    ... Do something here
    print("X1 variable is Null or None")
Answered By: M. Hamza Rajput

You can get this error with you have commented out HTML in a Flask application. Here the value for qual.date_expiry is None:

   <!-- <td>{{ qual.date_expiry.date() }}</td> -->

Delete the line or fix it up:

<td>{% if qual.date_attained != None %} {{ qual.date_attained.date() }} {% endif %} </td>
Answered By: Jeremy Thompson

When building a estimator (sklearn), if you forget to return self in the fit function, you get the same error.

class ImputeLags(BaseEstimator, TransformerMixin):
    def __init__(self, columns):
        self.columns = columns

    def fit(self, x, y=None):
        """ do something """

    def transfrom(self, x):
        return x

AttributeError: ‘NoneType’ object has no attribute ‘transform’?

Adding return self to the fit function fixes the error.

Answered By: Chiel
if val is not None:
    # no need for else: really if it doesn't contain anything useful

Check whether particular data is not empty or null.

Answered By: Shah Vipul

None of the other answers here gave me the correct solution. I had this scenario:

def my_method():
   if condition == 'whatever':
      return 'something'
      return None

answer = my_method()

if answer == None:
   print('Not empty')

Which errored with:

File "/usr/local/lib/python3.9/site-packages/gitlab/base.py", line 105, in __eq__
if self.get_id() and other.get_id():
AttributeError: 'NoneType' object has no attribute 'get_id'

In this case you can’t test equality to None with ==. To fix it I changed it to use is instead:

if answer is None:
   print('Not empty')
Answered By: David Newcomb
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